Crust: In a medium bowl, cut the shortening and salt into the flour with a pastry cutter or fork until the mix is pebbly. Add water in dribbles, stirring with fork until dough becomes somewhat sticky. Form dough into a ball, wrap with plastic and refrigerate for at least 1/2 hour. Filling: Squeeze lemon into a large bowl. Grate the lemon peel into the same bowl, taking care to avoid the white pith. Coarsely grate the peeled apples into the same bowl. Pour in the sherry and stir in the sugar. Mix well. In a small bowl, beat the eggs until light. In another bowl, cream the butter until soft, then add the eggs, blending well. Stir the butter and egg mixture into the sweetened fruit. Finish: Heat the oven to 400°, then roll the dough into a circle that is 2-3 inches wider in diameter than your pie shell or plate. Place the crust into th pie plate, and prick all over with a fork. Spoon in the filling and bake at 400° for 15 minutes. Reduce heat to 350° and bake for another 45 minutes, or until a knife inserted in the center comes out clean. Cool for at least 30 minutes before serving it warm.